JP-A 2011-253900 (Reference 1) discloses a multi-chip package (MCP) semiconductor device having a wiring substrate, a first semiconductor chip mounted on the wiring substrate, and a second semiconductor chip stacked on the first semiconductor chip so that an overhang portion is formed. In this semiconductor device, an insulation film formed on a surface of the wiring substrate is removed from a region of the wiring substrate that faces the overhand portion.
Furthermore, JP-A 6-326211 (Reference 2) discloses a semiconductor package having a circuit board and a semiconductor chip mounted on the circuit board in a face-down manner. A through hole is formed in a portion of the circuit board on which the semiconductor chip has been mounted. JP-A 11-97586 (Reference 3) also discloses a similar configuration to Reference 2.